I am a 8th grader at public school and just got a report card with all subject with A including math accelerated geometry.
But I got a B on my Physical Fitness.
I am thinking about going to schools like Choate Rosemary Hall and the Berkshire School and Peddie School.
Will this affect my admission much?
(I am also in the orchaestra and some school clubs also.)
What you should say is that you are thinking of applying to these highly selective schools. You can think about “going to” one of them once they accept you.
To answer your question, no, a B will not drastically affect your chances.